An Appendix containing a computer program listing is submitted on a compact disk, which is herein incorporated by reference in its entirety. The total number of compact discs including duplicates is two. Appendix A, which is part of the present specification, contains a list of the files contained on the compact disk. These listings contain material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the patent and trademark office patent file or records, but otherwise reserves all copyright rights whatsoever.
1. Field of the Invention
The present invention relates generally to computer networks and, more particularly, to collaborative computing over a computer network.
2. Description of the Related Art
Traditional collaborative computing tools allow computer users at different locations to communicate via a computer network and share documents or applications stored and/or executed on one the user""s computers. While both peer-to-peer and client-server communication models have been used in the past, web-based collaborative tools generally employ a client-server model.
For example, client-server application sharing (also discussed in the context of xe2x80x9cdistributed computingxe2x80x9d) is described in U.S. Pat. No. 5,434,852 xe2x80x9cDistributed Processing Architecture for Control of Broadband and Narrowband Communication Networks;xe2x80x9d U.S. Pat. No. 5,887,170 xe2x80x9cSystem for Classifying and Sending Selective Requests . . . ;xe2x80x9d and U.S. Pat. No. 6,038,593 xe2x80x9cRemote Application Control for Low Bandwidth Application Sharing,xe2x80x9d all incorporated herein by reference in their entireties. Other group communication techniques are described by Ulrick Hall and Franz J. Hauck, xe2x80x9cPromondia: A Java-Based Framework for Real-time Group Communication in the Web,xe2x80x9dProceedings of Sixth International World Wide Web Conference (Apr 7-11, 1997); Lane Boyd, xe2x80x9cTaking Collaboration Into Orbit,xe2x80x9d Computer Graphics World, Vol. 21, No. 9, p. 36 (Sept. 1998); and Eric Ly, xe2x80x9cDistributed Java Applets for Project Management on the Web,xe2x80x9d IEEE Internet Computing Online, Vol. 1, No. 3 (May/June 1997), all incorporated herein by reference in their entireties.
International Telecommunications Union (ITU) Standard T.120 is a family of open standards that provides both communications and applications protocols to support real-time multipoint data communications for collaboration and conferencing, among other uses. This standard is outlined in A Primer on the T.120 Series Standard by DataBeam Corp. (May 14, 1997), incorporated herein by reference in its entirety.
FIG. 1A is a block diagram illustrating the communication scheme used for an exemplary traditional collaborative computer system 100. In FIG. 1A, client computers 110n (where n=A, B, C . . . ) can connect to server computers 120n over a global-area computer network 130 (e.g., the Internet). As used herein, the numeral n appended to a reference number does not imply any correspondence among elements having different numerals (e.g., client computer 110A bears no relationship to server computer 120A). FIG. 1B is a block diagram illustrating the actual communications channels established between client computers 110n and server computers 120n to set up two conferences between users of client computers 110A and 110B on the one end and 110C and 110D on the other. As is readily apparent from inspection of FIG. 1B, each conference is handled by a single server computer 120n. This model performs satisfactorily for conferences having a small number of participants and conferences that do not require fault tolerance. However, as the number of participants in a conference increases, the computing power of server computer 120n becomes a bottleneck. Furthermore, if the particular server computer 120n that is handling a conference malfunctions, the entire conference is disrupted (i.e., server computer 120n represents a single point of failure for the entire system handling that conference). Accordingly, there is a need for an improved collaborative computing system.
The system and method of the present invention provide a distributed collaborative computer system that is scalable to handle an arbitrary number of conference participants and eliminates the server as the single point of failure in the system. This is accomplished by providing a plurality of server computers interconnected via one or more high-speed links. Client computers can connect to any available server computer and start or join a conference hosted on either the server computer to which the client computer is connected or any other server in the system. As a result, the system and method of the present invention is easily scalable to support an arbitrary number of participants to a conference by merely adding the appropriate number of server computers to the system. In addition, by replicating the conference information on more than one server computer, the system and method of the present invention eliminate the single point of failure limitation of prior art systems. In fact, if a server hosting or participating in a conference malfunctions, the failure is detected by other server computers and the client computer is able to reconnect to the conference through a new server computer.